Because the brains, sleep patterns, and eyes of children and adolescents are still developing, they are more vulnerable to the sleep-disrupting effects of screen time, per a recent review of the literature recently published in the journal Pediatrics.
First author Monique LeBourgeois shared, “The vast majority of studies find that kids and teens who consume more screen-based media are more likely to experience sleep disruption.” LeBourgeois, an associate professor in the Department of Integrative Physiology at the University of Colorado Boulder, continued, “With this paper, we wanted to go one step further by reviewing the studies that also point to the reasons why digital media adversely affects sleep.”
More than five dozen studies monitored adolescents aged five to 17 from all over the world, and 90 percent of the studies determined that more screen time is associated with “delayed bedtimes, fewer hours of sleep, and poorer sleep quality,” shared the authors, who also noted that biological, neurological, and environmental factors all play a role in their findings. The paper revealed that since their eyes are not fully developed yet, children are more sensitive than adults to the impact of light on the internal body clock.
LeBourgeois explained, “Light is our brain clock's primary timekeeper.” This means that when light hits the retina in the eye at night, it suppresses the sleep-promoting hormone melatonin, which delays the feeling of sleepiness and pushes back the timing of the body clock. She added, “We know younger individuals have larger pupils, and their lenses are more transparent, so their exposure and sensitivity to that light is even greater than in older individuals.”
In one study, both adults and school-age children were exposed to the same amount and intensity of light. Only the children's melatonin levels fell twice as much, shared the authors. Studies also support findings that short-wavelength "blue light," present in most hand-held electronics, is particularly notorious for suppressing melatonin.
LeBourgeois adds, “Through the young eyes of a child, exposure to a bright blue screen in the hours before bedtime is the perfect storm for both sleep and circadian disruption.” The authors note that digital media also adds “psychological stimulation,” like exposure to violent media or texting with friends, that can also sabotage sleep by upping cognitive arousal.
The authors added that children and adolescents whose phones or computers are left on overnight in their bedroom are more likely to have trouble sleeping. More than 75 percent of adolescents have screen-based media in their bedrooms, 60 percent interact with them an hour before their bedtime, and 45 percent rely on their phones as an alarm.
Digital Media and Sleep in Childhood and Adolescence is one of the 22 papers included in the first supplemental issue of Pediatrics that focused on screen time and youth health. Aside from summarizing past research, the papers aimed to set goals for future research, such as studying the impact of screen time on toddlers and preschoolers. (Related: Screen time found to have direct impact on speech delays in babies, reveals new research.)
Dr. Pam Hurst-Della Pietra, founder of the nonprofit Children and Screens that helped coordinate the study, noted, “The digital media landscape is evolving so quickly, we need our research to catch up just to answer some basic questions.”
If you're having trouble monitoring the gadget use of your kids, check out these tips:
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